Field of the Invention
This invention relates to the transformation of a sterile potato genotype where the resulting transgenic potato plant exhibits changes in plant morphology and ovule development and produces fertile seeds allowing for successful potato breeding and resulting in new improved cultivars. Removal of the transgene results in non-transgenic potato plants and non-transgenic potatoes displaying new traits.
Description of the Relevant Art
Cellulose binding domains (CBDs) represent a subset of carbohydrate binding modules. CBDs are found associated with the majority of saprophyte-encoded cellulolytic enzymes; however, they are generally not found associated with plant pathogen-encoded or with plant-encoded cellulolytic enzymes (Wang and Jones. 1995a. Appl. Environ. Microbiol. 61:2004-2006; Wang and Jones. 1995b. Gene 158:125-128). The principle function of CBDs is to mediate adherence to the carbohydrate substrate (Boraston et al. 2004. Biochem. J. 382:769-781; Nerve et al. 2010. Proc. Natl. Acad. Sci. 107:15293-15298). An additional function can be found in the ability of some CBDs to directly dissociate cellulose microfibrils (Lehtio et al. 2003. Proc. Natl. Acad. Sci. 100:484-488). Within the CBD families, there are a few examples of CBDs that are present as independent proteins, often associated with the cell wall. An example is CBD1 from the phytopathogen Phytophthora infestans (Jones and Ospina-Giraldo. 2011. PLoS ONE 6(8):e23555). The P. infestans CBD1 protein is found tightly associated with the cellulose-containing hyphal cell wall, and may play a role in assembly and/or integrity of the cell wall. This led to the idea that expression of this protein in potato plants may alter the host:pathogen interactions through binding to the host cellulose molecules, providing a potential shield from pathogen endoglucanases, or conversely, binding to Phytophthora hyphae, providing a shield from host endoglucanases.
Since the potato industry, like other parts of the agricultural industry, is facing many challenges, as for example, the problems associated with climate change, the spread of exotic pests and pathogens, a demand for reduced use of chemicals and a need for commercially important desirable traits, new strategies for obtaining improved varieties (cultivars) of potatoes are needed, particularly for those potato varieties that are popular and widely used, but are also sterile and thus not capable of being changed by conventional breeding practices.